01 F350 CC DRW 4WD Automatic trans. 140,000 miles.
I have a rebuilt 4R100 with 30,000 on it and getting ready to install sonix w/ springs. Also at same time flush trans and was wanting to go with mobil 1 synthitic (spelling).
Question, if both trans and transfer case take Mercon fluid, wouldn't hurt to change transfer case fluid at same time...two extra quarts (don't know history of fluid change on transfer case) why could I not use the same fluid in transfer case, Mobil 1 synthic, anyone have comments about this?

If I use the procedure I have seen on here quite a few times, changing from dino to synthitic, how much do you think I should run through it so as not to mix the synthitic and dino. Just remove and replace the 17 quarts or so, or should I be safe and get an extra 6-7 quarts (money is starting to be a issue with the synthitic...thanks for input.

 

I'd use the procedure as it's written. For a 2001 it says to use 20 quarts. That will change almost everything. The only way to get more is tear down the trans and clean everything.

 

I dont believe when you do the pump out method the transfer case gets flushed. there is a drain and fill plug on the transfer case, I also change ot everytime i do the tranny (every 20k). I do mine the old fashioned way, even changed the filter once already. I do take the cooler lines loose and blow the cooler and lines out with compressed air.AFter about the 2nd change i figured all the original fluid was finally gone,, Nothing but Mobil 1 In My tranny now.

 

MrBass is right. The transfer case is completly separate. You need to change the fluid out and the same ATF is spec for your transfer case as for your transmission. Yes use the synthetic of your choise. Mobil1, Redline, etc.

 

OK, may bad, I had two questions...I understand transfer case and trany are two completely individual items, fluid does not mix in the two.

Question 1-if changing trans from dino to synththic, how much extra synthitic should I flush through trans to clean out the dino? As I read from MRBASS I take it do the flush as written and by the second flush all the dino should be out...just didn't want them to mix (dino and synthic)

Question 2- answered, same spec for trans and transfer case, so I caan use same fluid in both...Thanks

 

Bug juice you'll never get all the old fluid out. But that won't hurt anything. Just drain as best as you can and refill.

 

Drain the torkconverder it has a drain plug. You may need to turn the flexplate to find it. Pull the black tin sheetmeatel cover off and roatate the flexplate to locate the drain plug. 5 or more qt of atf is in there it will refill buy it self.

 

I have a 2002 F250 7.3PSD w/4r100 tranny and i just drained the tranny fluid but couldn't find the drain plug on my TC. Took off the black cover...searched everywhere...rotated flexplate...don't know . Any suggestions?

 

E40d have one 4r100 should too

 

Yes, stop looking for it. The 2002 doesn't have a drain plug on the T/C. I wish that it did.
Joe

 

Thanks Joe...but how does one drain the TC'er?

 

I change mine by the 20 quart method. This way I not only flush the fluid out of the T/C but also flush it out of the lines and coolers. Click here:
https://www.ford-trucks.com/article/...nsmission.html

Joe

 

Wow sorry if i sent you on a wild goose chase under your truck.

 

Well my 02 has a drain Plug on the TC,, I have heard of several 02's that dont, but mine does, just have to rotate it to find the plug..
I dont use the flush method,, I just drain the TC,Tranny And the TRansfercase, then refill, and change filter every other change.After I drain everything I pull the lines and check the bypass valve and blow the lines out to the cooler.

 

Some early, early built '02 still had them. this is the year they phased them out.
MRBASS, is your new engine still stroking along fine?
Joe